A new detection method for cyclamen mite (Phytonemus pallidus) in strawberry

Cyclamen mite, Phytonemus pallidus (Banks) (Trombidiformes: Tarsonemidae), is a widespread pest of strawberry, feeding on new growth, and causing stunted plants and damaged fruit. Because of its small size (~0.25 mm) and cryptic lifestyle, cyclamen mite is often undetected until populations are high and plant injury is apparent. The objective of our research was to develop an end-point PCR-based method for detecting cyclamen mite from strawberry leaves.

Cyclamen mites were collected from eight fields in Ontario and Québec, Canada, and a sequence library of the barcoding region of the cytochrome c oxidase subunit I (COI) gene was created using the Lep F/R primer pair. Sequences were assembled and aligned in Geneious Prime. A primer set for a 94 bp amplicon was designed and tested by amplifying cyclamen mite DNA that had already been successfully sequenced with end-point PCR and visualizing bands on a 5% agarose gel. The primers differentiated cyclamen mite from 19 arthropods on strawberry, except for strawberry clipper weevil (Anthonomus signatus Say) (Coleoptera: Curculionidae). By amplifying decreasing concentrations of cyclamen mite DNA, primer sensitivity was determined to be 0.125 ng/μL. A strawberry leaf wash method was developed that successfully removed and recovered 90% of cyclamen mites from sampled strawberry leaves. Future experiments will be conducted to determine the feasibility of incorporating this detection method for cyclamen mite in the field and greenhouse on both strawberry plants and transplants. The outcome of this project will be a new method capable of detecting cyclamen mite at low population levels.